This invention relates to containers useful for the transport and storage of temperature-sensitive materials such as vaccines, antibodies, etc., for long periods of time in locations which lack conventional sources of electrical power.
In many developing countries, particularly in tropical and desert climates, there is a lack of sufficient refrigeration systems and, in many instances, there are no power capabilities to operate such refrigeration systems even if they were available.
The prior art systems available are based on refrigerator systems that freeze water to provide thermal storage temperatures of 0.degree. C. or below. Exposure of temperature-sensitive medicinals such as vaccines, etc., to these low temperatures frequently results in irreversible damage due to freezing of water which is an essential component to many of these medicinal products. On the other hand, storage of the medicinals at temperatures greater than about 10.degree. C. can also cause irreversible damage to the medicinals. Thus, there is an urgent need for a portable refrigerator system that operates to maintain the temperature within a narrow band above 0.degree. C. and below 10.degree. C. and which can operate where conventional electrical power lines are not available.